In recent years, near-to-eye (NTE) display devices have been developed and are becoming increasingly popular. Depending upon the particular end-use environment, these NTE display devices may be coupled to a helmet or headset of a viewer, and thus move with the changing position and angular orientation of the viewer's head. This advantageously allows the displayed information to be visible to the viewer regardless of the position and/or orientation of viewer's head.
It may thus be appreciated that determining the position and orientation of a viewer's head in six degrees-of-freedom (e.g., x, y, and z, and pitch, yaw, and roll) may be of particular importance to the overall functionality of NTE display devices. Many existing systems are relatively complex, heavy, and expensive. This is due, in part, to the fact that may are designed for military applications (e.g., helmet mounted systems), rather than a more compact, lightweight design, such as a visor.
Hence, there is a need for a high precision, high speed, relatively lightweight head tracking system that provides accurate and jitter-free registration and rendering of display elements on an NTE display device. The present invention addresses at least this need.